London: Even a bit of exercise can deliver a mental health boost to obese teenagers, says a new study. "The first thing I tell teenagers and parents struggling with their weight in my practice is to throw away the scale," said Gary Goldfield, researcher at the Children's Hospital of Eastern Ontario (CHEO) Research Institute.

"These kids face enough challenges with bullying and peer pressure today! This new study is proof positive that even a modest dose of exercise is prescriptive for a mental health boost," Goldfield was quoted in the Journal of Paediatric Psychology.

Being obese at any age is tied with diabetes and chronic fatigue to heart complications.Overweight adolescents are also at an increased risk of body dissatisfaction, social alienation and low self esteem, according to a Children's Hospital statement.

Goldfield, also associate professor of paediatrics at University of Ottawa, conducted the study with a group of adolescents aged 12-17 years who were required to undertake lab based sessions of stationary cycling twice weekly to music of their own choice or to an interactive video game for a 10-week trial.

All exercise was supervised and performed at light to moderate intensity. The music or interactive video game was used as a form of distraction from any perceived discomfort during the exercise, but participants could stop at their own choice at any time during a 60-minute session.

Although few physical differences emerged between the exercise groups over time, the teenagers did self-report improvements in perceived scholastic competence, social competence, and several markers of body image including appearance esteem and weight esteem.

"We're talking about psychological benefits derived from improved fitness resulting from modest amount of aerobic exercise - not a change in weight or body fat," continued Goldfield.

"If you can improve your physical activity and fitness even minimally, it can help improve your mental health. By teaching kids to focus on healthy active lifestyle behaviours, they are focusing on something they can control," concluded Goldfield.